1, 4, 5, 6‐Tetrahydro‐ν‐tetrazin‐Derivate

Abstract

1, 4, 5, 6‐Tetrahydro‐ν‐tetrazin‐Derivate The title compounds 2 and 13 are readily available from α‐lithiated N‐alkyl‐nitrosoamines 1 (see Tables 1 and 2) which decompose at − 73° to yield the N‐oxides 2. The ESR. spectra of two derivatives 1 are recorded (Fig. 1), and tentative mechanisms are proposed for the head to head dimerizations (la‐ 3‐ 4‐ 5‐ 2a and Scheme 1). Coupling of lithionitrosoamines with iodine (‐6) and alternative decomposition routes of representatives of this class of organometallics with special substitution [equations (2)‐(5)] are reported. The structures of the tetrazines are established by spectroscopic data [ESCA] (Fig. 2), IR., UV., 1H‐ (cf. Fig. 9) and 13C‐NMR., PE. (Scheme 2), by an X‐ray analysis of 2a (Fig. 4‐8 and Table 3), and by the chemical reactions. The crystal structure of 2a is a twisted boat with non planar terminal nitrogen atoms which reflects the electron repulsion in the 4‐atom‐6‐electron NNNN‐system. Comparisons are made with 2‐tetrazenes, the open chain analogues of 13, wherever possible. Raney‐Ni reductions of 2 or 13 gives diamines 14 to which is assigned the d, l‐configuration through the 1H‐NMR. spectra of the aminals 7 and 15. Neither the oxides 2 nor the tetrazines 13 undergo cycloaddition reactions [equation (6) and Section 4]. Compound 2a is dimerized to the bis (nitrosoamino)‐2‐tetrazene 18 by treatment with acid, ZnII, CuI or iodomethane. 2a is oxidized at nitrogen to the ethylene diamine derivative 6a (through 20, with H2O2), or at the CH2‐groups of the ring to give oxo‐N‐oxide 21 (with MnO2 or the ring contracted oxo‐tetrazoline‐N‐oxide 22 (with KMnO4). Pyrolysis or photolysis of the dimethyl tetrahydrotetrazine 13a furnishes the trimer 26 of N‐methylimine, but no diazetidine 27. Silver and mercury complexes 29 are obtained from 13a, while Cr(CO)5. THF does not furnish a complex as with azocompounds, but rather replaces N2 in 13a by CO (→ 28). Oxidation with permanganate converts 13a into the oxalic acid derivative 30 with unchanged tetrazine structure.

Synthesis of Unusual Oxime Ethers by Reaction of Tetranitromethane with B‐Alkylcatecholboranes

“…When an excess of piperidine is used only one nitro group is substituted. [26] Similar results were obtained with dibenzylamine, bis(4-bromobenzyl)amine and bis(naphth-2-ylmethyl)amine; compounds 17-19 were obtained in 39-50 % unoptimised yield. Compound 19 afforded single crystals suitable for Xray analysis, which confirmed the E geometry of the oxime moiety (see Figure 2 and the Supporting Information).…”

Catalytic Aerobic Oxidation of Hydrazines into 2‐Tetrazenes

“…Seebach et al. published another approach to 4 by oxidative dimerization of lithiated (and toxic) nitrosamines [37] …”

Ring Transformations in Tetrazole Chemistry

“…gen chain [74]. With the fused 1,2,3,5-tetrazinone derivative 85 the carbonyl group can be split out by alkaline hydrolysis, and the resultant triazene of type 15 is then cyclized oxidatively to the new bicycle 16a (cf.…”